2015 GMC Buick gallery

Vanderkaay/GMC, Handout

The 2015 Sierra 3500 features an all-new exterior designed to reduce wind noise and enhance powertrain cooling for more consistent performance. The Sierra 3500 offers class-leading available payload and conventional towing.

The 2015 Sierra 3500 features an all-new exterior designed to reduce wind noise and enhance powertrain cooling for more consistent performance. The Sierra 3500 offers class-leading available payload and conventional towing. (Vanderkaay/GMC, Handout)

Putting the heavy in heavy duty, this tow-friendly monster rounded out our trio. A 6.0-liter, V-8 turbodiesel churns out 397 horsepower and 765 pound-feet of torque an tow up to 13,000 pounds. It's bolted to a six-speed Allison automatic transmission.

Putting the heavy in heavy duty, this tow-friendly monster rounded out our trio. A 6.0-liter, V-8 turbodiesel churns out 397 horsepower and 765 pound-feet of torque an tow up to 13,000 pounds. It's bolted to a six-speed Allison automatic transmission. (GMC)